123 lines
3.3 KiB
Go
123 lines
3.3 KiB
Go
// Copyright 2022 The Gitea Authors. All rights reserved.
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// SPDX-License-Identifier: MIT
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package math
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import (
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"bytes"
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"github.com/yuin/goldmark/ast"
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"github.com/yuin/goldmark/parser"
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"github.com/yuin/goldmark/text"
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"github.com/yuin/goldmark/util"
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)
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type blockParser struct {
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parseDollars bool
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}
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// NewBlockParser creates a new math BlockParser
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func NewBlockParser(parseDollarBlocks bool) parser.BlockParser {
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return &blockParser{
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parseDollars: parseDollarBlocks,
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}
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}
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// Open parses the current line and returns a result of parsing.
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func (b *blockParser) Open(parent ast.Node, reader text.Reader, pc parser.Context) (ast.Node, parser.State) {
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line, segment := reader.PeekLine()
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pos := pc.BlockOffset()
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if pos == -1 || len(line[pos:]) < 2 {
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return nil, parser.NoChildren
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}
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dollars := false
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if b.parseDollars && line[pos] == '$' && line[pos+1] == '$' {
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dollars = true
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} else if line[pos] != '\\' || line[pos+1] != '[' {
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return nil, parser.NoChildren
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}
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node := NewBlock(dollars, pos)
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// Now we need to check if the ending block is on the segment...
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endBytes := []byte{'\\', ']'}
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if dollars {
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endBytes = []byte{'$', '$'}
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}
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idx := bytes.Index(line[pos+2:], endBytes)
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if idx >= 0 {
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segment.Stop = segment.Start + idx + 2
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reader.Advance(segment.Len() - 1)
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segment.Start += 2
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node.Lines().Append(segment)
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node.Closed = true
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return node, parser.Close | parser.NoChildren
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}
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reader.Advance(segment.Len() - 1)
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segment.Start += 2
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node.Lines().Append(segment)
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return node, parser.NoChildren
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}
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// Continue parses the current line and returns a result of parsing.
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func (b *blockParser) Continue(node ast.Node, reader text.Reader, pc parser.Context) parser.State {
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block := node.(*Block)
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if block.Closed {
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return parser.Close
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}
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line, segment := reader.PeekLine()
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w, pos := util.IndentWidth(line, 0)
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if w < 4 {
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if block.Dollars {
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i := pos
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for ; i < len(line) && line[i] == '$'; i++ {
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}
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length := i - pos
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if length >= 2 && util.IsBlank(line[i:]) {
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reader.Advance(segment.Stop - segment.Start - segment.Padding)
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block.Closed = true
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return parser.Close
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}
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} else if len(line[pos:]) > 1 && line[pos] == '\\' && line[pos+1] == ']' && util.IsBlank(line[pos+2:]) {
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reader.Advance(segment.Stop - segment.Start - segment.Padding)
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block.Closed = true
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return parser.Close
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}
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}
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pos, padding := util.IndentPosition(line, 0, block.Indent)
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seg := text.NewSegmentPadding(segment.Start+pos, segment.Stop, padding)
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node.Lines().Append(seg)
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reader.AdvanceAndSetPadding(segment.Stop-segment.Start-pos-1, padding)
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return parser.Continue | parser.NoChildren
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}
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// Close will be called when the parser returns Close.
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func (b *blockParser) Close(node ast.Node, reader text.Reader, pc parser.Context) {
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// noop
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}
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// CanInterruptParagraph returns true if the parser can interrupt paragraphs,
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// otherwise false.
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func (b *blockParser) CanInterruptParagraph() bool {
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return true
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}
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// CanAcceptIndentedLine returns true if the parser can open new node when
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// the given line is being indented more than 3 spaces.
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func (b *blockParser) CanAcceptIndentedLine() bool {
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return false
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}
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// Trigger returns a list of characters that triggers Parse method of
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// this parser.
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// If Trigger returns a nil, Open will be called with any lines.
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//
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// We leave this as nil as our parse method is quick enough
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func (b *blockParser) Trigger() []byte {
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return nil
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}
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